Burrowing Water Beetle

Superfamily Hydrophiloidea

Tarsi usually 5-5-5. Mostly aquatic in habit.

HISTER BEETLES Family Histeridae

Identification: Antennae elbowed, clubbed. FW short, truncate, exposing 1 or 2 abdominal segments. Body usually oval, sometimes greatly flattened, or elongate and cylindrical. Hard-bodied, shiny, black (some with red markings). 1-10 mm.

These beetles usually occur around decaying organic matter — carrion, dung, decaying plants, and oozing sap — and apparently feed on other insects attracted to these materials. Some species are very flat and live under loose bark. The elongate cylindrical species live in the galleries of wood-boring insects. Larvae have much the same habits as adults.

WATER SCAVENGER BEETLES Family Hydrophilidae Identification: Maxillary palps elongate, usually longer than antennae. Metasternum frequently prolonged posteriorly as a sharp spine. Body generally oval or elliptical, convex dorsally. Antennae short, clubbed. Hind legs flattened, usually with a fringe of hairs. Black, brown, or yellow, sometimes patterned. 1-40 mm.

This is a fairly large group of common insects very similar to the Dytiscidae (p. 154). Most species are aquatic, both as adults and larvae. Adults are principally scavengers, but larvae are predaceous. Larvae feed on a variety of aquatic animals, and are very voracious. The members of 1 subfamily (Sphaer-idiinae) are terrestrial, and feed in dung, humus, and decaying leaves.

MINUTE MOSS BEETLES Family Limnebiidae Not illus. Identification: Similar to Hydrophilidae but with 6 or 7 abdominal segments (5 in Hydrophilidae). Elongate-oval, dark-colored. Maxillary palps elongate. 1.2-1.7 mm.

Members of this small family are found in matted vegetation along streams, in decaying moss near the shore, and in swampy places. Larvae are predaceous.

SKIFF BEETLES Family Hydroscaphidae Not illus.

Identification: Similar to rove beetles (p. 160) in having FW short and truncate, exposing 3 abdominal segments, but oval, body widest at base of FW, and with notopleural sutures. Tarsi 3-3-3. Tan to brown. About 1.5 mm.

This family contains a single species that occurs in Arizona, s. Nevada, and s. California. Adults and larvae occur in streams, and are found on filamentous algae growing on rocks, especially in shallow water.

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